INTRODUCTION. 



9 



22.5 calories with a body-weight of 71.6 kg. Nine years later, in 

 1912, when he was studied in February and March by Zuntz and 

 Schirokich, and in May at the Nutrition Laboratory, the values ob- 

 tained per kilogram of body-weight were 19.2, 19.3, and 19.7 calories. 

 His basal metabolism at or about this time was thus a little over 19 

 calories per kilogram per 24 hours, which is distinctly low. Two fac- 

 tors, however, have an important bearing here. One is obesity, for, 

 with a height of 166 cm. and an age of 63 years, the normal weight 

 would be 65 kg.,^ while Mr. Fletcher's weight ranged from 76 to 

 82 kg. The excessive adipose tissue would tend to lower the heat 

 production per kilogram. Secondly, the element of age should be 

 considered, for, as has been shown by practically all the observations 

 thus far available, with advancing years there is a definite tendency 

 to a lowering of the metabolism. While, therefore, Mr. Fletcher's 

 metabolism was distinctly lower than the normal average, it is by no 

 means evident that this was due in any part to dietetic habits or to any 

 other known factor than those of age and obesity. 



The nitrogen output has a special interest in this connection when 

 considered as an index of the level of the protein katabolism. The data 

 for the nitrogen output for most of these subjects with presumably low 

 metabolism have been collected in table 2, which shows that Prof. C. 



Table 2. — Nitrogen excretion of subjects studied for low metabolism. 

 (Subjects post-absorptive.) 



* Introduced for comparison. 



has a nitrogen excretion per kilogram per hour of 8.3 mg. This is 

 somewhat higher than the average found for 10 subjects, including 

 Prof. C. and H. F., and reported by Benedict and Joslin,^ the average 

 for all subjects being 6.85 mg. On the other hand, both Dr. H. and 

 H. F. show a low nitrogen excretion, the average of two experiments 



1 Computed from table 4, Medico- Actuarial Mortality Inv., New York, 1912, 1, p. 38, deducting 



8 lbs. for clothing. 

 " Benedict and Joslin, Carnegie Inst. Wash. Pub. No. 136, 1910, p. 196. 



